In Sir Arthur C. Clarke’s 1972 novel Rendezvous with Rama, the explorers of a seemingly deserted alien spaceship passing through our Solar System encounter a strange three-legged creature that turns out to be an organic robot. In the ‘70s, this seemed so incredible that it could only be the product of an alien civilization thousands of years ahead of us. In 2012, scientists at MIT and the University of Pennsylvania are proving otherwise by starting work on organic robots here on Earth. Using genetically engineered muscle tissue that responds to light, they are blurring the line between animal and machine at the cellular level.